Forming usability professionals, particularly heuristic evaluators, is a challenging task. Heuristic evaluation is a well-known and widely employed usability evaluation method. A heuristic evaluation may be performed based on generic or specific heuristics. A key issue is how new heuristics are validated and/or evaluated; heuristic quality scales were proposed. The paper presents some recurrent problems when teaching the heuristic evaluation method. It also discusses novice evaluators’ perception over Nielsen’s usability heuristics, based on empirical data. The experiment that we made involved Computer Science graduate and undergraduate students, enrolled in a Human-Computer Interaction introductory course. 50 Chilean students and 18 Spanish students participated. The online travel agency Atrapalo.com was used as case study. We used a questionnaire that assesses evaluators’ perception over a set of usability heuristics. It rates each heuristic individually (Utility, Clarity, Ease of use, Necessity of additional checklist), but also the set of heuristics as a whole (Easiness, Intention, Completeness).